Published in:
Open Access 01-11-2018 | Original Article – Cancer Research
The gene mutational discrepancies between primary and paired metastatic colorectal carcinoma detected by next-generation sequencing
Published in: Journal of Cancer Research and Clinical Oncology | Issue 11/2018
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Purpose
To better understand the gene mutational status and heterogeneity between primary and metastatic CRC (mCRC) using a sensitive sequencing method.
Methods
The mutational status of EGFR, KRAS, NRAS, PIK3CA, ERBB2, BRAF, KIT, and PDGFRA was analyzed in 65 patients, with 147 samples of primary and paired live or lung metastatic CRC, using next-generation sequencing (NGS), quantitative RT-PCR (qPCR), and Sanger sequencing.
Results
Fifteen cases (15/22, 68.2%) of lung mCRC and thirteen cases (13/20, 65%) of liver mCRC harboured the same mutation profiles of KRAS, NRAS, or BRAF in the primary lesions. To all detected genes, 11 cases (11/22, 50%) of lung mCRC and 11 cases (11/20, 55%) of liver mCRC showed different mutational genes in the primary tumours. KRAS and BRAF mutations were more frequent in lung metastatic lesions (p = 0.004 and 0.003, respectively). The gene mutations in KRAS, NRAS, BRAF, and PIK3CA in the lung metastatic sites were more frequent than those in the liver metastatic sites (86.7 vs. 44%, respectively, p = 0.000). Some new mutations were not covered in the qPCR ranges but were detected by NGS.
Conclusion
The study demonstrated that the discordance of gene mutational status between paired primary and metastatic tumours is rather high when detected by NGS. Evaluating the mutational status of both the primary and metastatic tumours should be considered in clinical mutation testing.